In recent years surgery has markedly advanced through the performance of laparoscopic and endoscopic surgical procedures such as cholecystectomies, gastrostomies, appendectomies, and hernia repair. Also, the application of endoscopic surgical stapling and suturing instruments has been provided in cardiovascular and pulmonary surgery, as well as operative inventions in the gastrointestinal tract. Such endoscopic instruments are capable of providing hemostasis and also of cutting tissue. This reduces operating and recuperation time.
These stapling procedures are accomplished through a trocar assembly, which is a surgical instrument used to puncture a body cavity. The trocar contains a sharpened obturator tip and a trocar tube or cannula. The trocar cannula is inserted into the skin to access the body cavity, by using the obturator tip to penetrate the skin. After penetration, the obturator is removed and the trocar cannula remains in the body. It is through this cannula that surgical instruments are placed. Specifically, it is through this trocar cannula that surgical stapling instruments with cutting mechanisms are placed. One such trocar is the Endo-path.RTM.trocar manufactured by ETHICON ENDO-SURGERY, Cincinnati, Ohio.
Nonetheless, certain deficiencies in current concepts for endosurgical stapling mechanisms have been recognized. One of the more important deficiencies is the fact that current stapling mechanisms can not cause clamping of tissue and firing of the stapler, including the knife mechanism, with the same position of the hand for the forward stroke of an actuator, such as a trigger. Thus, the user must aim the clamping mechanism to encapture the desirable tissue with one hand, and then, while making a forward trigger stroke with the opposite hand, cause the tissue to be stapled and cut. If the stapling mechanism provides a ratchet member for the actuator, this deficiency is really not overcome, for in such a mechanism there still must occur simultaneous clamping and stapling of the tissue. Then, if it is undesirable to staple the tissue in that location, the trigger must be fully reversed. This may result in inadvertent jamming of the system, and in some staplers this alternative is simply not capable of being performed.
Another perceived deficiency is that no current stapling mechanisms have a safety device in place which prevents firing of the stapler before tissue has been clamped. Typically, the stapling mechanism may begin to clamp tissue between an anvil jaw and a stapling jaw. However, in some instances, there will be firing of the stapling mechanism before the tissue is entirely clamped. The user may have the mechanism partially attached to tissue via partially expelled staples before the user has ascertained a desirable location of the stapler. In this way, once again, there is a certain amount of instability or uncertainty in applying such a device.
A design criteria in creating a system containing two separate mechanisms for clamping and firing tissue is the limitation of the human hand. Therefore, it is difficult to properly and conveniently position a pair of triggers or a pushbutton mechanism coupled with a trigger mechanism. Thus, there has been little focus or incentive to create stapling mechanisms whereby the user is capable of operating a stapler with two strokes, unless both can be accomplished in a one-handed operation without moving that hand from the handle of the instrument.
Naturally, it would be desirable to be able to perform these functions in a fully rotational system. This simply allows the user to obtain virtually any angle of approach to the surgical site without having to contort the arm or wrist in order to adequately approach the subject.
Also, there have been no mechanisms which provide opening and closure of a clamping mechanism occurring during reciprocating motion of a clamping trigger. What is desired would be to be able to forwardly or reversedly move a trigger and thereby obtain closure or opening.
Finally, it would also be desirable to have distal contact of the stapling jaws, and then proximal clamping. In this way, once distal contact is effectuated, the surgeon realizes and can actually visualize the amount of tissue clamped between the jaws. By distal contact is meant that the distal or far end of the anvil seats first on the gap spacing pin or cartridge. Without such distal contact, the surgeon may still be uncertain about the amount of tissue clamped, and therefore the firing force necessary to fire the mechanism.